Ensure that we have a current kernel package installed

If no upgrades were available, the existing package needs to be
reinstalled, because the images in /boot were erased as part of the
original live CD build process, and we rely on them being present to
fix up the ISO later.

customize-inner.sh

@@ -31,13 +31,20 @@ EOF
 # And copy it for now (although it will get overwritten at boot)
 cat /etc/hosts.nilm >> /etc/hosts
 
-# Upgrade packages and remove old kernels
+# Upgrade packages
 apt update
 apt -y dist-upgrade
 apt -y --purge autoremove
-for VER in $(ls --sort=version /lib/modules/ | head -n -1) ; do
-    apt -y --purge remove "linux-.*$VER"
+
+# Remove old kernels, and reinstall the latest one (to make sure
+# it's present in /boot)
+LATEST_KERNEL=$(ls --sort=version /lib/modules/ | tail -n 1)
+for VER in $(ls --sort=version /lib/modules/) ; do
+    if [ $VER != $LATEST_KERNEL ] ; then
+        apt -y --purge remove "linux-.*$VER"
+    fi
 done
+apt -y --reinstall install linux-{,signed-}image-${LATEST_KERNEL}
 
 # Disable upgrade popups
 sed -i -s -e 's/Prompt=.*/Prompt=never/g' \